For many years the alarm clock radio has been the most commonly used device for waking people from sleep; however alarm clock radios are not the only devices capable of emitting a relatively loud alarm at a preset time. Mobile communication devices such as, for example, cellular phones and Personal Digital Assistants (PDAs) can also be employed.
Most mobile communication devices have a limited power source, like a battery. In order to conserve the available power, users typically turn off the devices when not in active use. Alternatively, the device may enter a low-power or “sleep” mode after a predefined period of inactivity.
In order to emit an alarm signal at a preset time, the devices typically need to transition to an active or power-on state. Many devices are capable of recognizing the occurrence of the preset alarm time even while in a power-down or sleep mode and they transition to a power-on or active mode at the preset time in order to issued the alarm signal. However many such devices have a boot period during which computer instructions need to be loaded into the device's RAM from the device's non-volatile memory. More complex devices, like PDAS, may include features, like a Java Virtual Machine, that may take several minutes to load and become active. The computer instructions to generate the alarm signal cannot be executed during at least a substantial portion of the boot period, and consequently an alarm may not occur until several minutes after the preset alarm time.
Accordingly, it would be advantageous to improve apparatus and methods for starting up a mobile communications device.
Similar reference numerals may have been used in different figures to denote similar components.